By ADAM NAGOURNEY

April 13, 2014

SAN DIEGO — Molly Whittaker is a chorus member with the San Diego Opera, where she has performed for almost 10 years. But the other evening she could be found outside the opera hall, wearing a bright red T-shirt reading “Fight for San Diego Opera,” and thrusting pamphlets and stickers at patrons as they arrived for a performance of Massenet’s “Don Quixote.”

“I’m trying to draw attention to myself,” she said, a note of urgency in her voice. The opera company announced last month that it would shut down after 49 years with the end of the run of “Don Quixote,” and she was on the front lines of a campaign to save it.

“I came home from babysitting, and it was on the news,” she said. “I fell on my knees and cried for two days.”

Ms. Whittaker appears to have failed. After a three-week battle that convulsed the community here and subjected its once revered opera company to widespread derision and accusations of mismanagement — Ian D. Campbell, its general and artistic director, was nearly booed off the stage when he stepped out to introduce “Don Quixote” this month on opening night — the board of directors on Friday reaffirmed its intention to close down. The final scheduled performance was on Sunday.

People here were certainly aware that their opera company, like so many others, was struggling with declining attendance and revenues. But the news still seemed to come as a shock, no matter how many urgent fund-raising appeals the troupe sent out. “You just get kind of used to that and take it with a grain of salt,” said Violet Huprich, 77, a retired teacher. “But there was no indication there was going to be a complete failure, that it was going to go down.”

The crisis comes at a time when even the Metropolitan Opera is struggling with many of the same kinds of problems and soon after the drawn-out demise of New York City Opera, which closed for different reasons. The seeming end of the line for this San Diego institution, the country’s 10th-largest opera company, gave fresh cause for alarm about the future of opera, and particularly regional opera. Unless there is a last-minute reprieve — a committee of four board members is making one final effort to find one — this metropolis of 3.1 million people, which prides itself as culturally rich, will have no place to see opera, short of chancing a drive to Los Angeles that can take anywhere from two-and-a-half hours to four hours each way.

The closing is another blow to a city that is still reeling from the embarrassing ouster of its mayor, Bob Filner, last year on sexual harassment charges. It means the loss of jobs for chorus members like Ms. Whittaker and others — a production of Verdi’s “A Masked Ball” last month required 288 people — and the shutting down of one more high-quality house for rising singers to gain experience and exposure.

“For anybody, it’s considered a huge notch on their résumé to have said that they worked here,” said Keturah Stickann, the New York-based director of “Don Quixote,” before a performance on Tuesday. “It’s known for bringing in the best in the world and has been for years and years and years.”

By the end, nightly attendance at the 2,500-seat Civic Theater here — the opera did not have its own hall — had fallen below 70 percent, even with seats discounted to fill the house. Ticket sales dropped to 34,674 last year from 41,355 in 2010. The Sunday performance was, not surprisingly, sold out, a bittersweet reminder of an earlier time.

“ ‘Elixir of Love,’ which got great reviews, still sold just 68 percent,” said Karen Cohn, chairwoman of the San Diego Opera, referring to a production of the Donizetti opera in February. “Lowest in our history. It was just devastating for us.”

It was a one-two punch: Even as ticket sales were dropping, the opera was depleting a $10.5 million endowment left to it by Joan Kroc — who died in 2003 and was the widow of Ray A. Kroc, who built the McDonald’s empire — to cover operating deficits. The Kroc fund is projected to be spent by the end of this month.

“Even if we sold out, the tickets are only covering 38 percent of the cost,” Ms. Cohn said. “Our donors are passing away; I don’t know if people are not being raised with opera in the United States any longer, but we are not selling out the operas anymore. Not even close.”

In the end, she said, the choice was to close “with dignity” now or proceed with a 2015 season that has already been scheduled and posted online — Wagner’s “Tannhäuser,” John Adams’s “Nixon in China,” Mozart’s “Don Giovanni” and Puccini’s “La Bohème,” complete with contracted singers who will still have to be paid — and face the embarrassment of an inevitable bankruptcy.

The drama in San Diego was particularly pitched and sudden, all the more striking given the context of the long, slow decline of New York City Opera.

“The leadership is just throwing in the towel,” said Carlos Cota, the business agent for the International Alliance of Theatrical Stage Employees Local 122, which represents opera workers in San Diego. “It’s just going to leave a dramatic void in our city.”

There has been no shortage of second-guessing the decision to close, and questioning whether the company did everything it might have — from considering smaller stages that might reduce ticket costs to being more experimental with its programming to attract new audience members. The disclosure of high executive salaries — Mr. Campbell made $489,000 last year, while his former wife, Ann Spira Campbell, who is deputy general director, drew $274,000 — only fanned the anger.

The sudden and mysterious decision to close also fed a storm of rumors that the two were trying to protect any severance payments. The board issued a statement from an independent lawyer saying that they would be treated the same as other opera creditors.

The troupe had a $15 million budget this year and was, unlike other companies, deficit free.

“A lot of opera companies face the same challenges,” said Marc A. Scorca, president of Opera America, an advocacy organization. “But other opera companies have soldiered on through creative reinvention, cutbacks in order to stabilize. They are going forward with a more diverse public program and a more diverse audience.”

“I think this is a story about one opera company,” he said. “It describes not the state of opera but the state of the company.”

Ms. Stickann said opera companies in Houston, Chicago and San Francisco had embraced change with no harm to their reputation. “These places are bringing in world-class musical theater and world-class chamber work, and I think that these are both options that would bring in a larger audience or a different audience,” Ms. Stickann said.

The concern echoed across the country. “They are dealing with the same head winds that all nonprofits are dealing with and they chose to pull the plug,” Christopher Koelsch, president of the Los Angeles Opera, said. “The things that were cited are some of the things that all of us have to deal with and the challenge to all of us is to adapt.”

Mr. Campbell disputed the notion that the board had not acted to avoid this moment, noting that it had cut back productions to four a year from five, and trimmed the staff. There was, he said, nothing left to do.

“We knew the problem was coming,” he said. “We took rather dramatic action in cutting expenses. Nobody stepped back. We all tried to do what we could. These are the cold, hard facts rather than emotions.”

Liam Dillon contributed reporting from San Diego, and Michael Cooper from New York.